Exercises: Characteristics of living things

Look at the diagram: a living thing carries out three life processes, labeled with letters A, B, and C. Name the life process represented by each letter, briefly describe what it involves, and give an example of an animal or plant carrying it out.

List the four most abundant bioelements in living things and explain what it means that all living things share a common chemical composition.

An earthworm, an oak tree, and a mushroom have very different sizes and shapes. State at least three shared characteristics that prove all three are living things.

Is a virus a living thing? Justify your answer considering which life processes it can carry out and which it cannot (viruses can only replicate when inside a host cell).

A salt crystal "grows" if more salt is added to its solution. Explain why this growth does not make the crystal a living thing, pointing out at least two differences compared to the growth of a plant.

A cat that hears a noise turns its ears towards it and freezes. Identify the stimulus and the response, state which life process it is carrying out, and explain why this is useful to the cat.

An archaeology team has found wheat grains in a sealed jar dating back 3000 years. A member of the team states: "They are completely dry, they neither move nor grow, so they are inert matter, exactly like grains of sand."

1. a) Design an experimental test to find out whether these seeds are still alive without having to wait weeks to see if a complete plant develops.
2. b) Several seeds are placed in an airtight jar with sensors at 20 °C, and it is found that the oxygen level drops from 20.9 % to 20.4 % in 48 hours, while carbon dioxide increases by 0.5 %. Interpret this result: what life process is being detected at the cellular level and what does it prove about the dormancy state of the seeds?

A classmate makes the following statement: "Plants like the pine tree feed on soil and fertilizer exactly the same way a deer feeds by eating branches; the only difference is that the deer moves around to look for food and the pine tree does not."

1. a) Refute their statement by explaining where each of these two living organisms actually obtains matter and energy.
2. b) Predict what would happen to the mass of the deer and the biomass of the pine tree if they are enclosed together in a large transparent dome where no matter other than water enters from the outside, but sunlight does. What if we cover the dome with an opaque tarp that completely blocks light? Justify the ecological role of each in both cases.

A robot vacuum cleaner moves around the house, avoids obstacles, and returns to its dock by itself to recharge its battery. Check each characteristic of living things one by one and conclude, providing arguments, whether the robot could be considered alive.